Compact sized choke coil and fabrication method of same

ABSTRACT

The present invention relates to a compact sized choke coil and fabrication method of same, an enameled metal wire or metal wire enclosed with insulated material is firstly prepared, then the wire is wound into helical coil, and then a magnetic film on the helical coil is formed by sputtering a layer of magnetic substance with a thickness greater than 10 −10  m on the surface of the helical coil, finally by electroplating, non-electroplating technologies, sol-gel method, crystal growth, or chemical vapor decomposition etc., suitable amount of magnetic substance is formed on the surface of said helical coil that has already been coated with a layer of magnetic material, and also fills the gap between and in the coil, after that, a block of compact sized choke coil is obtained.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a compact sized choke coil, especiallyto a conductive wire enclosed with insulated film is firstly wound intohelical coil, then magnetic substance is adhered as a thin coat on thehelical coil's surface by the technique of thin film process, crystalgrowth or other chemical process, by doing that, suitable amount ofmagnetic substance is then attached and filled onto the overall surfaceof the already coated helical coil and the spaces in between, such thatthe resulted helical coil can be compactized, meeting the need of chokecoil for compact digital devices.

2. Description of Prior Art

It is well known to public that the choke coil now available for sale,is made from electric wire that wraps around a magnetic core, but thesize of the mechanical structured magnetic core is too big for the needof today's light, thin, short and compact digital products, therefore,manufacturers in this field have conducted research, in hope to producea choke coil capable of meeting the requirement for serving the presenthigh technical digital devices.

Taiwan Patent Publication No. 1279818 discloses a method for fabricatinga choke coil, including the steps of: preparing a string of erected thinrectangularly profiled belt type conductor that has a downwardlyextended section at its both ends; with the conductor's one end asstarting point, winding the other end continuously towards the saidstarting point horizontally in circle to form horizontally erectedhelical coil; then bending the extended sections at the bottom of coiloutward to horizontal level, this makes inner extended section extendedfrom inside to outside, while the other extended section bendedhorizontally extended to outside; putting the helical coil inside amolding, with two extensions extend outside the molding; filling themolding with powdered magnetic substance, in order to enclose thehelical coil so no air or gap is existed in between the coil; settingthe molding to form a pair of trough on the surface of package holdingcoated helical coil; bending the coated coil's extended sections alongthe surface of coated coil after the molding is completed; and, puttingthe end of extended sections inside the trough formed on the package ofchoke coil.

However, the disclosed choke coil in said Taiwan Patent Publication No.1279818 is obtained firstly by putting the coil in a molding, then fillthe molding with powdered magnetic substance, and then apply pressingprocess. However, the choke coil produced according to the above methodhas some disadvantages. The primary concern is that, by using thisnatural filling and pressing method, as shown in FIG. 1, after thepressing process, the magnetic substance 2 which enveloping coil 1,obvious gap between magnetic substance 2 and coil 1 would be existed,which makes the two elements unable to completely get together, suchthat the volume of the produced choke coil cannot be reduced to aminimum scale. Also, the pressing process will cause damage to the coil,the final product will lead to unevenness of coil which in turn resultsin inaccuracy of measurement of inductance due to the damage of coilmentioned above.

Besides, because the above said conventional choke coil is produced byhigh mechanical pressure being applied to magnetic substance filled inmolding to mold the coil, the magnetic substance used to envelope thecoil will exceed the quantity actually needed, it not only is the reasonwhy conventional coil cannot be reduced in size, it also causesincreased production cost due to excess use of magnetic substance.

SUMMARY OF THE INVENTION

Therefore, the object of present invention is to provide a compact sizedchoke coil, which is covered by magnetic substance as a thin film on thesurface of the main body of coil, such that to protect the coil fromdamage occurred in conventional manufacture, and to improve theshortcoming of pressing process.

To achieve the above object, the compact sized choke coil of presentinvention is manufactured by: firstly preparing enameled wire or wireenclosed with insulated film, then winding the wire into helical coil,and then use sputtering method or other thin film processes, to form alayer of magnetic substance with a thickness greater than 10⁻¹⁰ m on thesurface of the said helical coil, putting the magnetic substance coatedhelical coil into a tooling, by using the processes of electroplating,crystal growth, or chemical vapor decomposition, to form proper amountof magnetic substance envelope over the helical coil coated withmagnetic substance, then a compact sized choke coil is formed.

The another object of present invention is to provide a compact sizedchoke coil, by utilizing sputtering or other thin film formationprocesses and electroplating, crystal growth or chemical vapordecomposition, not only make proper amount of magnetic substance adhereto the surface of main body of coil, the magnetic substance also fillsthe among the gaps of coil and the space surrounded by the coil, thenmakes the magnetic substance integrates with the coil completely, suchthat only right amount of magnetic substance is used while there is noexcess of magnetic substance, thereby to reduce the cost of producingchoke coil by eliminating cost of excess magnetic substance, the processcan further be applied to the production of compact sized choke coil.

The above objects and other advantages of the present invention willbecome more apparent by describing in detail the preferred embodiment ofthe present invention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing the fabrication method ofconventional choke coil as disclosed in Taiwan Patent Publication No.1279818.

FIG. 2 is an illustrative view showing enameled wire used in presentinvention.

FIG. 3 is an illustrative view showing compact choke coil of presentinvention in helical shape.

FIG. 4 is three-dimensional view and partially exploded view showingcompact choke coil of present invention adhered by magnetic substanceafter the substance is formed into film.

FIG. 5 is an illustrative view showing compact choke coil of presentinvention placed in a tooling.

FIG. 6 is a cross-sectional view showing choke coil in compact size ofpresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a compact sized choke coil, itsmanufacturing method consist the steps of:

-   1. preparing enameled wire 3, that is, a wire having its surface    enclosed with polymeric insulate material 30, as main body of coil's    material (as shown in FIG. 2);-   2. Winding said enameled wire 3 which is made by electric wire    having its surface enclosed with film of polymeric insulate material    30, horizontally into helical coil 4, the wire of helical coil is    wound very densely, the better one is in circular shape (as shown in    FIG. 3);-   3. by using thin film formation process such as sputtering, adhere    magnetic substance (such as iron, cobalt, nickel, etc.) of powder in    micro scale onto surface of helical coil 4, forming a layer of thin    film 5 as foundation with a thickness greater than 10⁻¹⁰ m, as shown    in FIG. 4, this magnetic thin film 5 adheres intensely with the    insulate material 30 enclosing onto the wire of helical coil 4;-   4. put the helical coil 4 into a tooling 6 (as shown in FIG. 5), the    size of the tooling must be just able to contain a proper amount of    magnetic substance sufficient to enclose the whole helical coil;-   5. by using the technique of electroplating, crystal growth or    chemical vapor deposition, makes the inner empty space 7 of tooling    6 filled with magnetic substance, this substance not only adheres to    the surface of magnetic film 5 outside the helical coil 4, but also    the outer surface of helical coil 4 and the space surrounded by    helical coil (as shown in FIG. 6);-   6. remove the tooling 6, and a compact choke coil is produced.

As the above manufacture steps are performing, because the magneticsubstance enveloping helical coil is formed through electroplating,crystal growth or chemical vapor deposition, such that the substance isformed to enclose helical coil 4, the choke coil manufactured by usingthis kind of technology can unify densely with its magnetic substance,and because the coil is so compact, the small quantity of magneticsubstance formed by electroplating, crystal growth or chemical vapordeposition is sufficient to fill in all the inner space of helical coil4 and wrap around the entire coil, forming a firm choke coil, thereby,the present invention do not cause the main body of coil any damage orunevenness due to the pressing process used in conventional art, itincreases the functionality of electronic component.

The compact sized choke coil of present invention uses the technology ofelectroplating, crystal growth or chemical vapor decomposition to formmagnetic material that wraps around the helical coil, the said formedmagnetic material has high density and do not occupy extra space, so nolarge amount with excess of magnetic substance occurs, the technologytherefore can be used in the production of even smaller choke coil ofchip scale.

Furthermore, the compact sized choke coil of present invention not onlycan use the technology of electroplating, crystal growth or chemicalvapor deposition to fill the magnetic substance in all the inner spaceof helical coil 4 and wrap around the entire coil, but also can use thetechnologies of non electroplating such as chemical plating, meltingplating (heat immersion plating), melting injection plating, vacuumplating, cathode sputtering, ionic sputtering, strike sputtering, zincheating method, or technology of sol-gel method.

In conclusion, since the compact sized choke coil and fabrication methodof same of present invention is not disclosed and for sale previously,and its unique character and ability are more advanced, it is thenbelieved that the present invention is an invention withprogressiveness, and meets the requirement of patent applicationaccording to Patent Law of Taiwan.

Although the present invention has been described with a certain degreeof particularity, the present disclosure has been made by way of exampleand changes in details of structure may be made without departing fromthe spirit thereof.

1. A compact sized choke coil, it consists of a helical coilcontinuously wound by electric wire, and two extensions extended fromboth ends of the coil as terminal; wherein the said coil is formed by anelectric wire enclosed with insulated film, the surface of said coil isenclosed with magnetic substance that combines fully with the insulatedfilm.
 2. The compact sized choke coil as claimed in claim 1, whereinsaid magnetic substance wraps around the main body of coil and fills theinner space surrounded by the coil.
 3. The compact sized choke coil asclaimed in claim 1, wherein the magnetic substance which encloses theinsulated film outside the wire are magnetic film, and the said magneticfilm has thickness at least 10⁻¹⁰ m.
 4. The compact sized choke coil asclaimed in claim 1, wherein the said magnetic material is iron, cobalt,or nickel.
 5. A method for fabricating compact sized choke coilincluding the steps of: Preparing enameled metal wire or metal wireenclosed with insulated film as the main body of coil; Winding saidenameled metal wire or metal wire enclosed with insulated film intohelical coil; Use thin film formation process to form a thin film ofmagnetic substance on the surface of coil; and By using electroplatingtechnology to make magnetic substance filling in the gap of main body ofchoke coil already coated with magnetic film and the inner spacesurrounded by the helical coil.
 6. The method for forming compact sizedchoke coil as claimed in claim 5, wherein the said magnetic substancethat encloses the whole coil and fills the inner space surrounded by thehelical coil can be obtained by the technique of crystal growth.
 7. Themethod for forming compact sized choke coil as claimed in claim 5,wherein the said magnetic substance that encloses the whole coil andfills the inner space surrounded by the helical coil can be obtained bythe technique of chemical vapor decomposition.
 8. The method for formingcompact sized choke coil as claimed in claim 5, wherein the saidmagnetic substance that encloses the whole coil and fills the innerspace surrounded by the helical coil can be obtained by the technologiesof non electroplating such as chemical plating, melting plating (heatimmersion plating), melting injection plating, vacuum plating, cathodesputtering, ionic sputtering, strike sputtering, zinc heating method, ortechnology of sol-gel method.